Not all Muslims started fasting on the same day this year.

Saudi Arabia, the UAE, Qatar, Bahrain, Yemen, Iraq, Lebanon, and Palestine declared Wednesday, 18 February, as the first day of Ramadan.

But Turkey, Singapore, Indonesia, Australia, and most of Europe said Thursday, 19 February. The reason comes down to how each country determines when the moon appears.

This one-day split happens regularly. But for the 1.9 billionMuslimsworldwide observing Ramadan — and the non-Muslims working alongside them, doingbusinesswith them, or simply wanting to understand — the difference matters.

Your Muslim colleague in London might be fasting today. Your supplier in Jakarta waits until tomorrow.

The split isn't an error. It's theology.

Saudi Arabia's Supreme Court relies on physicalmoon sightings. Witnesses scan the sky after sunset on the 29th day of Sha'ban, the month before Ramadan. Spot the crescent, and fasting begins the next morning. Miss it, and Sha'ban extends to 30 days.

Turkey and the European Council for Fatwa and Research use astronomical calculations. Their data showed the crescent was impossible to see on Tuesday evening — the moon sat too close to the sun for visibility. So, they declared Thursday.

Both methods are considered valid within Islamic jurisprudence. Many countries in Asia, Africa, and Oceania followed the calculation-based approach, according to Al Jazeera. The month ends with Eid al-Fitr, expected around 19 or 20 March, depending on the next moon sighting.

Ramadan moves backwards through the calendar by roughly 10 to 11 days annually. This year, it lands in late winter for the Northern Hemisphere. That means shorter days. Shorter fasts.

Source: International Business Times UK